Impulse-forming and like machines



July 4, 1967 F. BAKHTAR ETAL 3,329,003

IMPULSE-FORMING AND LIKE MACHINES I Filed Nov. 4; 1964 3 Sheets-Sheet 1 July 4, 1967 F. BAKHTAR ETAL 3,

IMPULSE-FORMING AND LIKE MACHINES Filed Nov. 4, 1964 s Shets-Sheet. 2

I Q I Wu '36 O 7 J M MM mfa LA 6 15W 19% 15W y 4,1957 F.'BAKHTAR ETAL' 3,329,003 IMPULSE-FORMING AND LIKE MACHINES 3 Sheets-Sheet 3 Filed Nov. 4, 1964 m w w 1 A i: 4 3 3 4, E. m 5 2/ R a q //A% I W mV// United States Patent 3,329,003 IMPULSE-FORMIN G AND LIKE MACHINES Farhang Bakhtar, Birmingham, Ian Marland, Evesham,

and Stephen Albert Tobias, Birmingham, England, assignors to National Research Development Corporation, London, England, a British corporation Filed Nov. 4, 1964, Ser. No. 408,931 Claims priority, application Great Britain, Nov. 5, 1963, 43,727/63 11 Claims. (Cl. 72-453) The invention relates to forming and like machines of the kind adapted to impart impulsive forces to a workpiece in order to perform a forging, shaping or like step on the workpiece. Usually in such machines the lower platen or other base for the workpiece support is fixed and the upper platen or the like is arranged to move downwards under the influence of an applied impulse to enable a desired impulse force to be imparted to the workpiece. The machine, therefore, differs from the steam hammer type of machine in which the force applied to the workpiece is derived from the momentum which the hammer or like body acquires when falling under gravitational forces; one of the main advantages of the impulsed machine is that the platen may be made considerably lighter than that of the hammer type of machine for equivalent impulsive forces imparted to the workpiece. Another advantage is that the direction of movement of the. platen need not be vertical. It will be observed that the maximum impulsive forces might be greatly increased by arranging for the opposing member to be impulsed in the opposite direction; however, difficulty arises in operation of such an arrangement when one of the moving parts is impulsed and the other not, by reason of faulty operation of the machine. It is an object of the present invention to provide a machine having this opposed motion but which may be arranged so as not to give rise to this difliculty.

In accordance with one aspect of the invention an impact-forming or like machine has opposed impacting parts and these parts are linked to move substantially simultaneously.

In accordance with another aspect of the invention an impact-forming or like machine has opposed-motion impacting parts and means is incorporated to ensure substantially equal division of effort between the two parts.

In a machine according to the invention, the impulse applied to each impacting part may be initiated normally independently of the other but linkage means between the two parts may ensure that the movement of the two parts is substantially synchronous. Said linkage means may be mechanical, but preferably it is hydraulic, and the presence of the linkage is arranged to ensure that, if an impulse is applied to one only of the impacting parts, then the impulse'is appropriately divided to impart substantially balanced impulses to both of the impacting parts.

Thus the two moving parts may each be associated with one or more pistons, the piston(s) associtaed with the one part being included in an hydraulic loop with the, or the corresponding, piston(s) associated with the other part. In an hydraulic arrangement, preferably there are two or more hydraulic loops, so that the transfer of effort from the one part to the other shall be as symmetrical as possible on the two parts.

In machines in accordance with the invention, the impulsive force applied to each moving part may be derived from the release of stored energy, such as from the release of compressed gas, from the ignition of explosive mixtures of gases such as described in the specification accompanying copending patent application No. 43,728/63 or from any other source of high energy.

In order that the invention may be better understood, embodiments thereof will now be described with reference to the accompanying drawings, of which FIGURES 1 and 2 are views at right-angles to each other showing diagrammatically the features of linked platen; FIGURE 3 indicates diagrammatically an adaption of the invention to enable the positions of the platens to be controlled;

and FIGURES 4, 5 and 6 show, respectively, in part-section a front elevation, a side elevation and a plan view, of one particular design of machine.

In FIGURES l, 2 and 3 of the drawings, the platens 1 and 2 are shown, for simplicity, Without guide pillars on which they are arranged to slide, nor are the impulsive means indicated. However, it is seen that the upper platen is connected to part 5 of a piston assembly at the back of an hydraulic loop 3 and to a part 6 of a similar piston assembly at the front of a second hydraulic loop 4, while the lower platen 22 is connected, at the front, to a part 7 of another piston assembly in loop 3 and, at the back, to part 8 of another piston assembly, in loop 4. The piston assemblies in each loop are connected by hydraulic fluid and in consequence any movement of platen 1 is transmitted to platen 2 and, vice versa. Thus if, in operation, it should happen that the impulsing device for one of the platens should fail to operate synchronously with that of the other platen, or even if it should fail to operate altogether, movement of the other platen is transmitted through the hydraulic loops so that both platens move in any event. The effort from the impulsing means is shared by the platens, and possibly only half the total effort results in the case of complete failure of one of the impulsing devices, but there is no danger of full powered impact from the one platen only on the workpiece or of overtravel of the one platen, if the workpiece is attached to one or other of the platens, so that the consequential strain on the machine is avoided. Of course, when both impulsing devices correctly function, the effort which is imparted to the workpiece is double that which could be applied between the upper moving platen as shown and a fixed lower platen, as in existing machines of this kind.

In accordance with a feature of the invention, means are provided in impact-forming or like machine having opposed impacting parts for inching the impacting parts, for instance, for positioning and/ or adjustment purposes. Means is preferably provided for re-setting the impulse mechanism and/or for locking the impacting parts in a stationary position, as a safety measure.

Thus in FIGURE 3, which is a similar view to that of FIGURE 2, the insertion of a stop valve 9 renders it possible for the platens 1 and 2 to be prevented from movement, that is by closure of the valve, making it necessary to perform the operation of opening it in order to operate the rriachine. In order not to restrict flow of fluid too greatly when under an impulsed stroke, it is preferable that the valve 9 should have at least the same bore when open, as the hydraulic tube.

In addition, valves 10 and 11 may be included .in supply lines for the hydraulic fluid filling the systems, so that when valve 9 is closed, fluid can be pumped into the system through valve 10 to move the platens into their open positions, valve 11 releasing fluid from the other part of the loop to enable the piston assemblies to move. Manipulation of the valves 10 and 11 to cause injection of fluid through either valve and release of fluid through the other, will enable the operator to move the platens to any intermediate position that may be required; and by closure of all these valves, the platens may be locked in any desired position. It will be understood that, when the machine is provided with a plurality of hydraulic loops, then a valve such as 9 will be provided in more than one of the loops. If the return and/or inching facilities are required, valves 10 and 11 need be provided in association with a valve 9 in one loop only.

Referring now to the machine which is the subject of FIGURES 4, 5 and 6, the two platens 12 and 13 are arranged to operate on guide pillars 14 and 15, which are Supported between pairs of box griders 16 and 17 respectively.

Each platen co-operates with a hollow piston 18, the part 19 of which seals against the end plate 20 of a cylinder 21 surrounding the piston 18; an O-ring seal 22 completes the seal.

The two parts of the die member 23 are secured respectively to the platens 12 and 13 by means of bolts which are not shown; piston 24 operates within the end of each piston 18 to eject a finished component from the respective die member 23. Hydraulic fluid for ejection is introduced from pressure cylinders 25 which are themselves operated by auxiliary cylinders 43.

In operation high air pressure is built up in each cylinder 21. The pistons 18 are held against the O-rings 22 due to the differential pressures acting on the parts 19 when vents 29 are open to atmosphere to hold the platens in position. At each end, the cylinder 21 and the piston 24 are in communication through the vents 27 in the piston 18 and through vent 28 in the piston itself which is therefore retracted when the pressure build-up occurs in the cylinder.

When it is desired to operate the machine for a forming operation, the vents 29 in the end plates 20 are opened substantially simultaneously to a source or sources of compressed air, and the resulting impulsive forces applied to the parts 19 forces each to break its seal on to the end plate 20 and the very high pressure air thereupon acts over the full area of the piston 18 to provide an impulsive movement of the platen. It might happen, however, that the operating means for opening the vent 29 on one or another of the platen-operating cylinders 21, fails to open that vent and only one platen would be impulsed. In order to safeguard the machine in such a contingency, platen 12 carries a bridging piece 30 which is connected to a piston assembly 31, 32 of an hydraulic loop 33, 34, 35 and 36, the ends of the loop being completed by cross-bored end pieces 35, 36. A bridging piece 37 connected to piston assembly 38, 39 in the same hydraulic loop, is carried by the lower platen 13 and the two platens are therefore linked together. A second hydraulic loop is provided on the other side of the machine, as is evidenced by a similar cross-bore end piece 40 therefor (FIGURE 6). It follows from the foregoing description of the arrangement of FIGURES 1 and 2, that the platens are postively linked and that any abnormal operation of one or other of the impulsing cylinders, which affects operation of the respective platens, results in operation of the other platen also being affected so as to divide the total impulsive forces substantially equally between the two platens.

A valve 41 is provided in the hydraulic loop 33-36 and closing or opening of this valve is arranged to lock the platens in position or to release them, respectively. A toggle device 42 is provided to bias the valve positively in the closed or in the open position so as to prevent accidental operation of the valve. If desired, valve arrangements for inching and/ or positioning may be provided in similar manner to those provided in the case illustrated in FIGURE 3.

It will be appreciated that the arrangement shown in FIGURES 4, 5 and 6 provides a neat, compact machine occupying little floor space, compared with, say, a steam hammer of the same capacity. Also, because both platens are impulsed they can be mounted vertically and floor space is even less than would be required for a machine in which the lower platen were fixed and the upper platen energised by the two impulse cylinders arranged side by side to give the same impact energy. By use of at least the one aspect of the invention, it is possible to operate an opposed impulse machine without undue fear of strain in the machine because of the hazard of faulty operation of the impulse cylinders.

Other benefits will be apparent to those skilled in the art.

We claim:

1. An impulse forming machine having opposed-motion impacting parts, positive linkage means directly interconnecting said opposed-motion impacting parts such that movement thereof is substantially simultaneous.

2. An impulse forming machine having opposed-motion impacting parts and positive linkage means directly interconnecting said opposed-motion impacting parts to ensure substantially equal division of effort between the two parts.

3. An impulse forming machine having opposed-motion impacting parts, the impulse applied to each impacting part being initiated normally independently of the other and positive linkage means directly connecting the two parts to ensure that movement of the two parts is substantially synchronous.

4. An impulse forming machine as claimed in claim 8, wherein each of the two impacting parts is associated with at least one piston, the piston associated with the one part being included in an hydraulic loop with the piston associated with the other part.

5. An impulse forming machine as claimed in claim 4, wherein a plurality of said hydraulic loops and associated piston arrangements is provided, the pistons being distributed in relation to said parts so that the transfer of effort between the two parts is substantially symmetrical.

6. An impulse forming machine as claimed in claim 3, wherein the impulsive effort applied to each said impacting part is derived from the release of stored energy of a compressed gas.

7. An impulse forming machine as claimed in claim 3, wherein the impulsive eifort applied to each said impacting part is derived from the release of the chemical energy of a compound.

8. An impulse forming machine having opposed-motion impacting parts, the impulse applied to each impacting part being initiated normally independently of the other and hydraulic linkage means connecting the two parts to ensure that movement of the two parts is substantially synchronous.

9. An impulse forming machine having opposed-motion impacting parts, the impulse applied to each impacting part being initiated normally independently of the other and linkage means connecting the two parts such that if an implied impulse is initiated to only one of the said impacting parts, that impulse is appropriately divided to impart substantially balanced impulses to both of the impacting parts.

10. An impulse forming machine as claimed in claim 8 wherein means are provided for controlling the relative spacing of said parts prior to the initiation of the impulse for impacting movement of each part.

11. An impulse forming machine as claimed in claim 8 wherein means are provided for locking the impacting parts in spaced apart stationary position.

References Cited UNITED STATES PATENTS 2,149,641 3/1939 Temple 78-42 X 2,655,002 10/1953 Terhune 78-42 X 2,729,943 1/1956 Clarke et al. 78-42 X 3,135,140 6/1964 Ottestad et al 7842 WILLIAM W. DYER, ]R., Primary Examiner.

GERALD A. DOST, Examiner. 

1. AN IMPULSE FORMING MACHINE HAVING OPPOSED-MOTION IMPACTING PARTS, POSITIVE LINKAGE MEANS DIRECTLY INTERCONNECTING SAID OPPOSED-MOTION IMPACTING PARTS SUCH THAT MOVEMENT THEREOF IS SUBSTANTIALY SIMULTANEOUS. 